aura: Remove WindowTreeHost::OnDeviceScaleFactorChanged.

ui/views/widget/desktop_aura/desktop_window_tree_host_win.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/views/widget/desktop_aura/desktop_window_tree_host_win.h"
 
 #include "base/win/metro.h"
 #include "third_party/skia/include/core/SkPath.h"
 #include "third_party/skia/include/core/SkRegion.h"
 #include "ui/aura/client/aura_constants.h"
@@ skipping 487 matching lines @@
 }
 
 void DesktopWindowTreeHostWin::ReleaseCapture() {
   message_handler_->ReleaseCapture();
 }
 
 void DesktopWindowTreeHostWin::PostNativeEvent(
     const base::NativeEvent& native_event) {
 }
 
-void DesktopWindowTreeHostWin::OnDeviceScaleFactorChanged(
-    float device_scale_factor) {
-}
-
 void DesktopWindowTreeHostWin::SetCursorNative(gfx::NativeCursor cursor) {
   ui::CursorLoaderWin cursor_loader;
   cursor_loader.SetPlatformCursor(&cursor);
 
   message_handler_->SetCursor(cursor.platform());
 }
 
 void DesktopWindowTreeHostWin::OnCursorVisibilityChangedNative(bool show) {
   if (is_cursor_visible_ == show)
     return;
@@ skipping 425 matching lines @@
 
 // static
 DesktopWindowTreeHost* DesktopWindowTreeHost::Create(
     internal::NativeWidgetDelegate* native_widget_delegate,
     DesktopNativeWidgetAura* desktop_native_widget_aura) {
   return new DesktopWindowTreeHostWin(native_widget_delegate,
                                       desktop_native_widget_aura);
 }
 
 }  // namespace views